I'm new to ruby so I have no clue what I'm doing yet here. I downloaded active_merchant code and attempted to run some tests using active_support 1.3.1. That work just fine for me. I upgraded rails to 1.2rc1 and it then downloaded active_support 1.3.1.5618. When I attempt to run the same tests now with active_support I'm getting an error because of the new version of active support. I was thinking I could just specify the older version of active_support and all would be well but that doesn't seem to be working. Instead of doing: begin require 'active_support' rescue LoadError require 'rubygems' require_gem 'activesupport' end I changed this to: begin require 'rubygems' require_gem 'activesupport', '<=1.3.1' rescue LoadError require 'rubygems' require_gem 'activesupport' end I also tried just putting in require_gem 'activesupport', '1.3.1' with no luck. The error I get is something like 'mattr_accessor' is undefined. I've read that you can specify the version of a gem so I must be doing something stupid here. I have put in a ticket on the rails list about this issue with activesupport but I was hoping to work around the issue til it was fixed. Thanks in advance. -- Posted via http://www.ruby-forum.com/.